Photo-platemaking process and apparatus therefor

ABSTRACT

A photo-platemaking process for making a printing plate and apparatus for accomplishing the process.

United States Patent -'llsulooi et a1.

[ 1 Aug. 26, 1975 [54] PHOTO-PLATEMAKKNG PROCESS AND APPARATUS THEREFOR [75] Inventors: Masayoshi Tsuboi; Kotaro Sato,

both of Asaka; Junichi Takanashi, Minami-Ashigara, all of Japan [73] Assignee: Fuji Photo Film Co., Ltd.,

Minami-Ashigara, Japan [22] Filed: Feb. 7, 1973 [21] Appl. No.1 330,346

[30] Foreign Application Priority Data Feb. 7, 1972 Japan 47-13441 [52] US. Cl. 96/33; 96/29 L [51] int. Cl. G03F 7/02 [58] Field of Search 96/29 L, 33

[56] References Cited UNITED STATES PATENTS 2,448,861 9/1948 Colt 96/33 2,494,053 10/1950 Mitson et a1 96/33 3,385,701 5/1968 Ormsbee et a1. 96/29 L 3,511,656 5/1970 Regan et a1. 96/29 L 3,620,737 11/1971 Etter 96/33 3,625,687 11/1971 Dunkle 96/33 3,814,602 6/1974 Shinozaki et al.... 96/29 L 3,814,603 6/1974 Mukaido et a1. 96/29 L OTHER PUBLICATIONS Hartsuch, P. D., Chemistry of Lithography, (1961), Reprinted 1963, LTF, lnc., New York, N.Y., pp. 152 & 153.

West Germany, OLS 2,048,594, April 1971, Mukaida et al., 23 pp. spec, 2 sh. dwg.

Primary Examiner-David Klein Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zion and Macpeak [5 7] ABSTRACT A photo-platemaking process for making a printing plate and apparatus for accomplishing the process.

The photo-platemaking process comprises the steps of (1) image-wise exposing a plate substance for making a photo-plate which consists of a hydrophilic surface part or a hydrophilic layer provided on an oleophilic support and containing therein silver depositing nuclei for diffusion transfer, a silver halide emulsion layer being superimposed thereon; (2) developing the same to form a positive silver image on the hydrophilic surface part or on the hydrophilic layer; (3) washing with water to remove the silver halide emulsion layer; (4) subjecting the hydrophilic surface part or the hydrophilic layer to an etchbleaching treatment to thereby expose the oleophilic surface part which corresponds to the silver image; and (5) subjecting the assembly to after-treatment whereby any residue deteriorated due to the etchbleaching treatment is rendered fragile for removal.

The apparatus for photo-platemaking consists of: (a) a plurality of twin rollers to convey the plate sub stance for making a planographic printing plate; (b) a developing trough, a washing trough, an etchbleaching trough and an after-treating trough for accomplishing the corresponding treatments of the plate substance; (c) means for removing the silver halide emulsion layer in the washing trough, and (d) means for removing the etchdeteriorated residue in the after-treating trough.

The present apparatus may be combined with a photographing device comprising: (i) a manuscript supporting bed; (ii) a magnification controlling device for determining the position of a photographic lens according to the photographic magnification desired; (iii) a camera to photograph a manuscript on the plate substance (which has been housed in a magazine) by means of the lens; and (iv) means to convey the photographed plate substance in the form of a roll to a photoengraving device and means to cut off the conveyed part in order to automatically and continuously perform the photographing operation and the photo-platemaking operation.

14 Claims, 3 Drawing Figures PATENTED AUG 2 61975 Illll PHOTO-PLATEMAKTNG PROCESS AND APPARATUS THEREFOR The present apparatus may be combined with a photographing device comprising; (i) a manuscript supporting bed; (ii) a magnification controlling device for determing the position of a photographic lens according to the photographic magnification desired; (iii) a camera to photograph a manuscript on the plate substance (which has been housed in a magazine) by means of the lens; and (iv) means to convey the photographed plate substance in the form of a roll to a photoengraving device and means to cut off the conveyed part in order to automatically and continuously perform the photographing operation and the photoplatemaking operation.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo-platemaking process and apparatus therefor, more precisely, to a process for photo-platemaking a sheet material which consists of a hydrophilic surface part or a hydrophilic layer provided on an oleophilic support and a lightsensitive halide emulsion layer superimposed on the surface part or the layer and to apparatus for accomplishing the photo-platemaking process.

2. Description of the Prior Art Various processes have hitherto been proposed for photoplatemaking using as a photo-sensitive layer a light-sensitive silver halide emulsion layer, which proccsses have. however, various defects. For example, the process described in US. Pat. No. 2,448,546! uses as a photosensitive substance a dichromate. In this process, the photosensitive region of the photosensitive substance is mainly in the ultra-violet region, and not only is the sensitivity of the substance low but also the preservability ofa photosensitized sheet substance produced therefrom is extremely poor.

According to the processes described in Japanese Pat. Publication No. 27242/69 or U.S. Pat. NO. 3,385,701, the printing plate consists of an oleophilic support and a hydrophilic layer applied on the surface of the support. These processes, however, involve various defects in that the adhesion of the surface of the oleophilic support and the hydrophilic layer is low, and as a result the hydrophilic layer in non-imaged parts is apt to be easily separated from the surface of the support during printing and the hydrophilic surface may be stained due to the deposition of oily inks thereon. The hydrophilic layer used in these processes consists of gelatin, colloidal silica, etc, and the hydrophilic property ofthe layer is not always sufficient. Therefore, oily inks gradually deposit on non-imaged parts with in creased amounts of printing until the hydrophilic surface is stained. Thus, sufficient numbers of printed reproductions of high quality cannot be obtained.

Apart from the above mentioned conventional processes, British Pat. Nos. 913,591 and 998,447 describe processes for making lithographic printing plates wherein a metal plate, such as an aluminum plate having a hydrophilic surface, is used, the metal plate having activity to reduce a silver salt by a diffusion transfer process, and an oleophilic silver image is formed on the metal plate whereby the silver image forms an oleophilic part. However, aluminum is easily oxidized by air to form aluminum oxide, and thus the activity thereof as diffusion transfer nuclei is poor. Moreover, the den sity of the silver image deposited is apt to be low, and accordingly, it is necessary in the process of British Pat. No. 913,591 to use a specific treating solution including a chemical agent which has an affinity to the silver image deposited in order to improve the oleophilic property of the silver image deposited. In British Pat. No. 998,447 a treatment with a strong alkaline solution such as a lithium hydroxide solution is required to dissolve the aluminum oxide layer.

Silver salt diffusion transfer processes are well known in the art and in these processes imagewise unexposed silver halides of a photosensitive silver halide emulsion are imagewise converted into distributions of a soluble silver complex, and the complex is then diffused in silver depositing nuclei which convert the soluble silver complex transferred by diffusion into silver.

German Patent Laid Open for Publication Inspection (OLS) 2,048,594 describes an improved photolithographic process free from the above mentioned defects. More precisely, the process comprises the steps of, after imparting an original image exposure to a photo sensitive sheet material which consists of an organic acid cellulose ester sheet having a hydrophilic surface part containing a nuclei substance for a diffusion transfer process and a light-sensitive silver halide emulsion layer applied on the hydrophilic surface, forming a re versal silver image corresponding to the original in the hydrophilic surface by means of a diffusion transfer process, and then treating with an aqeous solution containing hydrogen peroxide to remove the hydrophilic surface in places where the silver image is present to thereby expose the oleophilic surface of the organic acid cellulose ester sheet.

In this process, however, it is necessary to strongly rub the hydrophilic surface during etch-bleaching in order to expose the oleophilic surface, and due to the rubbing hydrophilic parts often remain or scratches are made. As a result it is difficult to completely expose the oleophilic surface. Moreover, when the hydrophilic surface part is thinned so that the oleophilic surface may be exposed by lightly rubbing the same, the nonimage area is apt to be stained during printing, and thin lines will be defaced.

SUMMARY OF THE INVENTION The present invention provides an improved photoplatemaking process which is free from the defects of conventional processes and apparatus for accomplishing the improved process.

The objects of the present invention are to provide the following;

1. A process for making a printing plate which can yield a great number of print reproductions of high quality.

2. A photo-platemaking process which may be conducted by only one operator.

3. Apparatus for a photo-platemaking process for making printing plates which can yield a great number of print reproductions of high quality.

4. Apparatus for a photo-platemaking process which can be automatically conducted by only one operator in a light room.

5. An automatic processing system for a photoplatemaking process which can automatically produce a printing plate from which a number of print reproductions of high quality can be made, and which system can be operated by only one operator in a light room.

The above objects can be attained according to the process of the present invention which is characterized by the steps of, after image-wise exposing a plate consisting of a hydrophilic surface part or a hydrophilic layer provided on an oleophilic support and a silver halide emulsion layer superimposed on the hydrophilic surface part or layer, developing. washing with water, subjecting to an etch-bleaching treatment and then subjecting to an after-treatment.

Apparatus to accomplish the above purpose comprises, in combination. means to convey the plate substance being processed sequentially through a developing trough, a washing trough. an etch-bleaching trough and an after-treatment trough containing treating solutions to accomplish the indicated purpose, means for removing the silver halide emulsion layer in the washing trough and means for removing the deteriorated residues in the after-treatment trough.

In a further embodiment the apparatus described above is combined with photographing means to expose the plate substance which comprises a manuscript (original) supporting bed, means to control the desired magnification of the original for exposure of the plate substance, means in which the plate substance is exposed and means to convey and forward the exposed plate substance to the apparatus described in teh proceeding paragraph. If the plate substance is in the form of a roll, cutting means is provided to cut the plate substance to the desired length prior to developing, etc.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of treating apparatus embodying the present invention cut along the direc tion of a photosensitive material for a printing plate which is being conveyed.

FIGv 2 is a side view of one embodiment of the present apparatus.

FIG. 3 is aside view illustrating the interior ofa magazine box.

DETAILED DESCRIPTION OF THE INVENTION The hydrophilic surface part which has been provided on an oleophilic support defines a construction where at least one surface of a plastic sheet is hydrolyzed to render it hydrophilic. The hydrophilic surface part and the oleophilic layer are thus integral and the hydrophilic surface part has excellent mechanical strength, different from the hydrophilic layer as will be explained hereinunder. Accordingly, the hydrophilic surface part does not easily peel off from the oleophilic support. The total sheet thickness is usually about 80 to 300p. considering the strength of the support, the cost, and ease of handling, though greater and lesser thicknesses can be used. The thickness of the hydrophilic surface part is thinner than that of the sheet and is about 0.1 to about 30p.,preferably about 0.3 to about p. and most preferably 0.33,u..

The plastic sheets are those where the contact angle of water is more than 45 before the hydrophilic treatment, but less than 45 after the hydrophilic treatment, at normal temperature. Representatives of plastic sheets which can be treated as above are, for example,

organic acid cellulose ester sheets such as a cellulose diacetate sheet, a cellulose triacetate sheet or a sheet made of a mixture of these two acetates, a cellulose acetate sheet, a cellulose propionate sheet, a cellulose butyrate sheet. a cellulose acetate butyrate sheet or the like. or an inorganic acid cellulose ester sheet such as a cellulose nitrate sheet; a polyvinyl ester sheet such as a polyethylene terephthalate sheet, a polystyrene sheet, a polyvinyl acetate sheet or the like; a polyvinyl acetal type sheet such as a polyvinyl acetal sheet, etc.

The surface part of these sheets may be made hydrophilic by hydrolyzing the same with an alkaline agent. In some cases, other treatments may be performed to impart the hydrophilic property to the surface apart. These treatments include, for example, acid hydrolysis of polyvinyl acetal, or modifying polyethylene terephthalate, polystyrene, etc. by using dichromic acid or nitric acid, or oxidizing the same by means of ozonohigh frequency discharge. Processes as are typically used are taught in US. Pat. Nos. 2,448,86] and 2,494,053. Representative treatment baths are g NaOH, 400 cc ethyl alcohol, water to make I liter and 200 cc 10% NaOH, 400 cc ethyl alcohol, l0 cc acetone, I000 cc water.

In the thus obtained hydrophilic surface part there are introduced silver depositing nuclei such as heavy metals, e.g., cadmium, tin, zinc, chromium, nickel, cobalt, etc., noble metals such as gold, platinum, palladium, etc., or sulfates or selenates of each of these heavy metals or noble metal salts, e.g., SnCl AgNO silver-citrate and the like. These materials are known to the art. See, for example, Paper presented at the conference in Liege, Apr. 15-17, 1948, by Hautot, US. Pat Nos. 2.698.237, 2,698,238. 2,774,667 and 2,698,245.

The silver depositing nuclei may be introduced in the hydrophilic surface part simultaneously with or after rendering the same hydrophilic.

To introduce the silver depositing nuclei the above mentioned silver depositing nuclei can be dispersed in water to form a colloidal dispersion and then contacted with the hydrophilic surface part. In this case. alcohols, ketones or chlorinated hydrocarbons can be used. These solvents have the capability particularly to swell celluloses, and so when celluloses are used it is preferable to use these solvents singly or in the form of a mixture or together with water so that the nuclei may easily be introduced into the celluloses. Accordingly, it is a most preferred embodiment of this invention to use organic acid cellulose ester sheets of the above mentioned plastic films by imparting a hydrophilic property to such ester sheets.

Representatives of the alcohols and ketones as are used include, for example, methyl alcohol, ethyl alcohol, propyl alcohol. iso-propyl alcohol, butyl alcohol, ethylene glycol, propylene glycol, polyethylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Particularly preferred are solvent mixtures such as water-methyl alcohol, water-ethyl alcohol-acetone, etc., since these can accelerate the hydrolysis.

The concentration of the nuclei substance can vary greatly as is known to the art, for example the concentration of NiS will generally be from as little as about 5 X I0 mole/l to as great as about 5 X lO mole/l.

The temperature of nuclei introduction is usually from about 15 to about C and usually can be up to about C less than the bp of the solvent. with a preferred range being 20 to 50C.

The reaction time will vary depending upon the temperature, e.g., at 50C 5 seer-60 sec.. at 35C 20 see.- l20 sec. and at 20C 35 see.-240 see.

On the other hand, the hydrophilic layer provided on an oleophilic support means a hydrophilic colloid layer coated on a plastic sheet as described above. Examples of the hydrophilic colloids include, for example, gelatin derivatives such as gelatin, phthalated gelatin, etc., casein, alginates, polyacrylic acid, maleic acid anhydridemethyl methacrylate copolymers, vinyl derivatives (e.g. polyvinyl alcohol, polyvinyl pyrrolidone) or salts thereof such as the metal salts, e.g., Na, K, Li, NH, salts.

The thickness of such a layer is usually from about 0.3a to about lOu, preferably 0.3g. to 3p. When the thickness is too great, it is difficult to conduct the etchbleach.

For introducing silver depositing nuclei into the hydrophilic layer, the above mentioned silver depositing nuclei are dispersed in the hydrophilic colloid aqueous solution as heretofore described and applied onto an oleophilic support.

On the above described hydrophilic surface part or on the hydrophilic layer there is coated a silver halide emulsion layer, with a preferred thickness of the dried emulsion being from In to p and a preferred amount of silver being from 30a g/cm to 900p g/cm".

The ratio of silver halide: binder is not important. In general, the silve halide emulsion layer is coated and dried on the hydrophilic surface part or the hydrophilic layer and the thus coated plate is then stored. When the plate is to be used, the same may be image-wise exposed. The emulsion layer is preferably non-hardened or slightly hardened, so that development may easily be performed.

The silver halide emulsion is one which has been prepared by dispersing an emulsion of a silver halide as is generally known and used in the photographic field. such as silver chloride, silver bromide, silver iodide, silver bromochloride, silver bromoiodide, silver bromoiodochloride, etc, in the above mentioned hydrophilic colloid. The silver halide emulsion can include additives as are generally used in the photographic field, such as a color sensitizer, fog preventing agent, stabilizer, hardener, surfactant, etc.

A natural or synthetic high molecular weight material layer such as an intermediate layer, protective layer or the like may be provided between the hydrophilic surface part or the hydrophilic layer and the silver halide emulsion layer, and, if desired, pigments, may be incorporated in the hydrophilic layer or intermediate layer.

The exposed silver halide emulsion layer is then developed such that the silver halide emulsion layer is contacted with the hydrophilic surface part or the hydrophilic layer. For the development, a developer for a diffusion transfer process which contains a solvent for dissolving the silver halide, such as sodium or potassium thio'sulfate, is used. The exposed silver halide emulsion layer and the hydrophilic surface part or the hydrophilic layer are dipped into the developer, more particularly, the layers are preferably dipped in the developer together with the oleophilic support from the viewpoint of ease of treatment. The developers used are well known in this photographic field, and are described in detail in Processing Chemistry" written by Mason (The Focal Press, 1966). in the present invention, the developers used can be selected from known diffusion transfer developers without any special critical selection to the exact developer used, though typically they are developers having hydroxy groups and amino group at the ortho or para-position, e.g., dihydroxybenzenes such as hydroquinone, chlorohydroquinone, bromohydroquinone, toluhydroquinone, tbutylhydroquinone, p-methyl phenolsulfate, triaminophenol, pyrogallol, alkoxy substituted hydroquinones, the amino/phenol group compounds often being used as a salt, e.g., of HCl, H 80 3-pyrazolidones, e.g., l-phenyl-3-pyrazolidone, e.g., 4-amino-5,6-dihydroxydimethyl pyrimizine, etc.

The developers are used in their art recognized amounts, e.g., 5-35 g/l for the dihydroxybenzenes.

The silver halide dissolving agents can be selected from those known to the art, e.g., NaSCN, KSCN and Na S- Q, and are used in an amount as in common in this art, e.g., 4 g/l to g/l.

In the process of the present invention when a nonhardened or slightly hardened emulsion is used for the purpose of performing the treatment speedily and in a stable manner, the development must be conducted at a temperature such that the emulsion layer is not melted. This temperature is, in general, lower than 30C. On the other hand, the lowest limit of the temperature is preferably higher than 0C for purposes of preventing the developing speed from being too slow. The most generally used practical developing temperature are lO-35C, preferably l5-25C. The developing time can easily be determined by those skilled in the art according to the kind of developer, the developing temperature and other conditions, and is usually from 10 sec to 50 sec., preferably 20-40 sec.

After a positive silver image is formed on the silver depositing nuclei by diffusion transfer development, the silver halide emulsion layer becomes unnecessary, and so this layer is removed from the hydrophilic surface part or the hydriphilic layer by washing with water. In this treatment, when the above mentioned protective layer or intermediate layer is present it is removed together with the emulsion layer.

The temperature for the washing with water is selected to make the removal of the emulsion layer from the hydrophilic surface part or the hydrophilic layer easy, and in general is at least C, with a minimum of C providing better results. A preferred operational range is -55C. The hydrophilic surface part is peeled from the oleophilic support only with difficulty, as compared with the hydrophilic layer, and so when the hydrophilic surface part is used the emulsion layer can be peeled therefrom by means of a roller or the like without injuring the hydrophilic surface part.

In the water used for washing there may optionally be incorporated accelerating agents such as a protein decomposing enzyme, thiocyanate, urea, etc., which render the washing with water easier to accomplish.

The hydrophilic surface part or the hydrophilic layer which has been washed with water is then subjected to an etchbleaching treatment. The etch-bleaching treatment is a means to expose the oleophilic surface corresponding to the silver image part. According to this treatment, the hydrophilic surface part or the hydrophilic layer corresponding to the image part is deteriorated. The term deterioration means the phonomenon that the hydrophilic surface part or the hydrophilic tions, such as sodium ferrihexacyanate di-chromate,

hydrogen peroxide, etc. In particular, peroxodisulfate has good stability in solution, and so peroxosulfate or peroxodisulfate are a preferred oxidizing agents. These may be used singly or in the form of a mixture thereof, and a most effective amount is 0.35-30% by weight of the treating solution.

In order to accelerate the etching action, at least one of a cupric salt, an acid or a substance which reacts with silver to form a complex of low solubility can be present in the etching solution. Examples of useful cupric salts include water soluble cupric salts such as cupric chloride, cupric bromide, cupric nitrate, cupric sulfate, cupric citrate, etc. Cupric halides are preferred. Examples of useful acids include organic acids such as acetic'acid, citric acid, tartaric acid, phthalic acid, maleic acid, benzene sulfonic acid, etc., and inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid. etc.

Examples of substances which react with silver to form a compound of low solubility include halides, tartrates, carbonates, chromates or formates. In particular, halides are preferred, e.g., NaBr, KCl, KBr, LiBr, NH Br, Nal, Kl, SrBr. etc.

Accelerators and/or such materials which react with silver are described in, for example, US. Pat. No. 3,385,701, British Pat. No. 587,957 and OLS. 2,048,594. 9

These accelerating agents may be used singly or in the form of a combination thereof. The amount of ac celerating agent is usually 0.05 -50% by weight of the treating solution. (Some compounds have a solubility of lower than 50%, but an amount thereof more than 0.05% will suffice.)

When peroxodisulfate is used together with at least one of the above mentioned etching accelerating agents (cupric salt, acid or substance which reacts with silver to form a complex of a low solubility), the

amount of the pcroxodisulfate is, calculated in terms of ammonium peroxo-disulfate, ().Ol25-30% by weight of the treating solution.

The preferred amount of the peroxodifulfate is, calculated in terms of ammonium peroxo-disulfate, (ll-2071 by weight, considering the stability of the etching solution with the passage of time and the stability of the photosensitive material. Using this solution the parts of the hydrophilic layer corresponding to the silver image are etched at 40C within 30 seconds and are deteriorated.

The etch-bleaching temperature is usually 5-45C, preferably to 40C considering the stability of the etching-bleaching solution with the passage of time and the reaction speed. The etch-bleaching time can vary greatly but from 10 to 60 sec. will suffice for most elements processed.

The preferred etch-bleaching solutions contain an oxidizing agent, an acid, and a material which forms an insoluble compound with silver, e.g., see British Pat. No. 587,957, US. Pat. No. 833,274, US. Pat. No. 3,385,701 and OLS 2,048594.

The surface of the sheet material treated by etching is lightly rubber whereby the hydrophilic surface part corresponding to the silver image is easily removed and thus the oleophilic surface of the sheet is exposed. On

the other hand, the hydrophilic surface part free of silver image remains as such. The thus manufactured printing plate can be used as is as a direct or offset printing plate according to conventional processes. In addition, the plate can subjected to an after-treatment to obtain a desired planographic printing plate having better properties.

The term after-treatment defines a treatment whereby the residues which have been deteriorated by the aforementioned etchingbleaching treatment are rendered fragile and, for example, comprise treating the hydrophilic surface part or the hydrophilic layer which has been subjected to etching-bleaching with a solution of a chlorine-oxygen acid such as chlorous acid, hypochlorous acid or perchloric acid or a salt of such an acid, a water soluble thiocyanate, a dyestuff which is physical adsorbed to the hydrophilic surface part of the hydrophilic layer and having (an) anion substituent(s), or a mixture thereof.

The fragile residues which result have been deteri orated by the etching-bleaching treatment and they may be completely removed by this after-treatment, or, in certain cases, may be easily removed merely by lightly wiping the surface by means ofa sponge, cotton, wool, etc., without injuring the hydrophilic surface part or the hydrophilic layer in the non-image part, whereby operational efficiency is extremely improved. The printing plate finally obtained yields print reproductions having extremely high sharpness and resolving power.

When the hydrophilic surface part embodiment is used a particularly superior effect can be attained by the after-treatment.

1n the non-dyestuff emobdiments of the after treatment the temperature is generally from about 5 to about C. preferably 10 to 40C., with the concentration of active ingredient generally being from 0. l -307c, preferably O.2-5%, by weight, based on one liter of after treatment both, though in the case of KSCN, the concentration is advisably 0.1 to 20%, and in the case of NaClO, it is acceptable to use 2-30 mols /1' of NaClO containing 10% effective Cl per liter.

As examples of the dyestuffs mentioned above, there are direct dyes, basic dyes, naphthol dyes (coupling components of azoic dyes), acid dyes, etc. as described in the Japanese book entitled Handbook for Dyes (published by Maurzen Publishing Co. in I970), pages 83 and 245-246. Examples of anionic substituents as are used include the sulfonic group, sulfinic group, CO group, CS group, carboxylgroup, etc., in the form of an acid and/or a salt, e.g., an Na, K or Nl-l4 salt.

The direct dyes contain one or more anionic substituents such as sulfonic groups, etc. In the after-treatment of the present invention, any type of the direct dye may be used, and particularly preferred dyes are for example: C.l. Direct Yellow 1 1, Cl. Direct Yellow l2, C.l. Direct Yellow 26, CI. Direct Yellow 39, CI. Direct Yellow 44, Cl. Direct Yellow 50, Cl. Direct Orange 6, CI. Direct Orange 8, Cl. Direct Orange 10, Cl. Direct Orange 26, Cl Direct Orange 39, C.l. Direct Orange 49, Cl. Direct Orange 51, Cl. Direct Red l, C.l. Direct Red 2, CI. Direct Red 4, Cl. Direct Red 9, CI. Direct Red. 13, CI. Direct Red 20, CI. Direct Red 23, Cl. Direct Red 28,01. Direct Red 31, C.l. Direct Red 37, Cl. Direct Red 62, CI. Direct Red 79, C]. Direct Red 80, Cl. Direct Red 81, C.l. Direct Red 83, Cl. Direct Red 89, C.l. Direct Red 224, CI. Direct Red 225,01. Direct Red 226, C1. Direct Red 229, CI. Direct Red 230, CI. Direct Violet 47, Cl. Direct Blue 1, Cl. Direct Blue 71, Cl Direct Blue 78, Cl. Direct Blue 86, C.l. Direct Blue 98, Cl. Direct Blue 106, etc.

Many basic ldyes contain cationic groups, for example, Mehtylene Blue, Malachite Green Crystal Violet, Victoria Blue, etc., and do not contain any anionic substituent. Such basic dyes cannot be used in the present invention. On the other hand, basic dyes containing anionic substituents, for example, C.l. Basic Violet 1O (Rhodamine 13), etc. can be used in the present invention whereby the same effect as in the case of the above mentioned direct dyes can be attained.

The naphthol dyes which can be used are naphthol series substances which are coupling components of azoic dyes, for example, 2-hydroxy-naphthalene-3- carbonyl-anilide-4'-sodium sulfonate, etc. In other words, the naphthol dyes are substances that have as a base skeleton the 2-hydroxy-3-naphtho-anilide group. Accordingly, compounds that contain additional substituent(s) and/or condensed ring(s) in the naphthalene nuclei and/or benzene nuclei of the 2-hydroXy-3- naphthoic acid anilide are included in the class of naphthol dyes which can be used in the present invention, e.g., alkyl, alkoxy, phenyl. anthraquinone, etc., substituted materials.

Acid dyes containing anionic substituents are, in general, inferior to the direct dyes with respect to physical adsorbability to plastics, especially to hydrophilic cellulose at normal temperature. However, when the temperature of the aqueous solution of the dyes is elevated, eg, to 50 to 90C, the physical adsorbability may be improved and thus such dyes can be used in the present invention at such elevated temperatures. Representatives of such acid dyes are, for example C.l. Acid Yel low 19, Cl. Acid Yellow 99, etc.

Most of acid dyes containing anionic substituents are similar to those mentioned above, but some acid dyes can provide the same effect as the direct dyes even at normal temperature. Although this class of dyes is very limited, such acid dyes are effective in the present invention, and include, for example, C.l. Acid Blue 158, C1. Acid Red 186, CI. Acid Red 265, etc.

The above mentioned direct dyes, basic dyes, naphthol dyes and acid dyes can be used singly or as mixtures of two or more thereof.

The concentration of the solution of these dyes can vary, depending upon the kind of the dyes used, the properties of the layer to be etched such as the degree of hardness, kind, thickness, etc. ofthe layer, as well as the temperature of the solution of the dyes. While the concentration will thus vary depending on a number of factors, in general the dye is present in an amount of greater than 0.01% by weight of the solution. The dyes can also be used in the form of a supersaturated solution at a certain temperature and in a certain solution constitution. Preferably, the solution contains about 0.55% by weight of the dyes.

The pH value of the solution of the dyes may be acidic, neutral or alkaline state, but in particular the alkaline state is preferred, with a neutral to weakly alkaline state of pH 7ll being most preferred. Accordingly, usually an appropriate adjustment of the pH of the dye solution will be performed, if necessary. For this adjustment, an alkali such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, etc., or an acid such as acetic acid, sulfuric acid, hydrochloric acid, nitric acid, etc. is used.

The temperature of the solution of the dyes to be used is, in general, in the range of 290C, and more preferably 1050C. The treating period varies, depending upon the properties of the layer to be etched, the constitution of the solution of the dyes, etc. In general, the treating period is in the range of from for 5 seconds to for 5 minutes.

To the solution of the dyes which contain at least one anionic substituent and which physically adsorb onto the hydrophilic surface part or the hydrophilic layer of the present invention, additional organic solvents which are miscible with water may be added as auxiliary solvents, for example, a solvent containing a hydroxyl group(s) such as methanol, ethanol, ethylene glycol, isopropyl alcohol, etc., a ketone series solvent such as acetone, methyl-ethyl detone, etc., or an ether series solvent such as ethylene glycol monomethyl ether, ethylene glycol diethyl ether, etc. Generally from 260% organic solvent based on solution weight can be used, with organic solvents in a small amount (2207( in water being more preferred.

The use of such an after-treating solution containing dyes imparts an especially excellent effect to cellulose having a hydrophilic surface part or to cellulose having a hydrophilic layer.

The treatment by the use of such treating solution is, in general, performed after the treatment by the use of the etching-bleaching solution. Water washing may be performed between these two treatments.

According to the above mentioned after-treatment, various advantageous effects as mentioned above may be attained, and thus, a printing plate of high quality may be obtained from which a number of print reproductions having a high sharpness can be produced.

An additional effect is as follows: When the above mentioned dyes other than the naphthol dyes are used the dyes are adsorbed only on the non-image parts which are not etched, and so various kinds of colored reversal images can be obtained according to the kind of the dye used. Therefore, when the after-treatment of the present invention has been performed during processing in a photo-platemaking process, the question of whether or not the etching process was complete or whether or not the reproduction of a namuscript is sufficient can usually be confirmed without inking the obtained printing plate. As a result, the operational efficiency of the present process is improved.

When a printing plate obtained by the present invention is brought to a heat projector before being inked eyestrain does not occur since the difference between the part colored with dyes and that not colored is extremely vivid.

It should be noted that generally speaking the development, water washing, etch-bleaching and aftertreatment can be completed within 15-45 seconds, and with the use of the apparatus described below extremely rapid and efficient processing could be conducted, e.g., in from 1 minute to 3 minutes.

The apparatus for the photo-platemaking process of the present invention will be now explained with reference to the drawings attached hereto.

With reference to the FIG. 1, 10 is the overall apparatus assembly. Each of treating troughs 22A-22D is filled with treating solution to be used in the present photo-platemaking process. Apparatus 10 has almost the same construction as a conventional automatic treating machine which is used for DP work (photographic development and printing), etc., with the exception of sponge rollers 27 and pressing plates 28 placed in the fourth through 22D. which will be explained hereinunder.

A brief explanation of apparatus 10 is as follows: the treating throughs 22A to 22D consist of troughs of a developing bath 22A. a water wahsing bath 228. an etching-bleaching bath 22C and an after-treating bath 22D. The conveyance of the substance to be treated is performed by means of roller twins 24 and guide plates 23 and 25, that is, the conveying means is a roller conveyance.

Heaters 26 and devices for cooling water circulation 36 are optionally provided for the purposes of cntrolling the liquid temperature. A taking-up lid 32 is provided for the purpose of taking up the plate treated in the first trough 22A and the second trough 22B, and in general lid 32 is shut to exclude light from the interior of the treating troughs. The developer may be checked according to the degree of development of the developed plate.

A detailed explanation will now be given, with reference to apparatus shown in the FIG. I with respect to how to treat and process the printing plate of the present invention consisting of a hydrophilic surface part or a hydrophilic layer which contains silver depositing nuclei for diffusion transfer and which has been provided on an oleophilic support, with a silver halide emulsion layer superimposed on the surface part or the layer.

The plate to be used for printing which has been photographed by means of a camera for photoen'graving or the like is brought into the interior of apparatus 10 by means ofa guide plate 19, and is then successively conveyed to the first trough, the second trough, the third trough and the fourth trough in this order, finally forming a printing plate.

The first trough 22A is a developing bath. This trough is filled with a developer consisting of the components described above at O30C. The plate is conveyed into the developing bath whereby the exposed silver halide emulsion layer on the plate is subjected to a diffusion transfer development. When the plate has reached the outlet of the first trough 22A. a positive silver image is formed in the hydrophilic surface part or the hydrophilic layer of the plate.

The second trough 22B is a water washing bath. The plate passed through the first trough is forwarded into the water washing bath 228 along the guide plate where the silver halide emulsion layer is removed. When auxiliary layers such as the protective layer. intermediate layer or the like are present, these layers are also removed at the same time. The water for washing is warm water having a temperature of. higher than 40C. For the removal of the emulsion layer. it is sufficient to provide a' rotary removing means or the like in this trough which does not impart damage such as scratches or the like to the plate substance. In particular, it is especially effective to provide pairs of rollers in the second trough to make the linear velocity of the rotary device different from the conveying speed of the plate whereby a higher effect is attained.

In FIG. I one embodiment is shown ofa removing device consisting of sponge rollers 27 and pressing plate 28. The sponge rollers 27 may also be placed so as to face each other. The removing means is not limited to sponge rollers. The rotary removing device can optionally be provided at the outlet of the water washing bath 228.

In the plate sent out from the second trough 223, the silver halide emulsion layer is removed off and the hydrophilic surface part or the hydrophilic layer which contains a silver image is exposed.

The third trough 22C is an etch-bleaching bath. The plate forwarded from the second trough 228 to the third trough is subjected to etch-bleaching treatment in the third trough. The various conditions such as the composition of the liquid supplied to the third trough. the temperature of the liquid and the like may be selected from a wide range as in the case of the treatments in the first trough 22A and second trough 228. By the etchbleaching treatment, the hydrophilic surface part or the hydrophilic layer corresponding to the image part is deteriorated. In this stage. the plate can be used as a printing plate, but will usually not yield sufficient print reproductions. The plates thus subjected to the etching-bleaching treatment are further conveyed to the fourth trough 22D.

The fourth trough 22D is an after-treating bath wherein the plate which has been subjected to etchbleaching treatment is after-treated. The aftertreatment means, as mentioned above, is to make the hydrophilic surface part or the hydrophilic layer which has been deteriorated by means of the etch-bleaching solution brittle. Accordingly, the plate sent out from the fourth trough 22D may be used as a printing plate as such, or by merely rubbing the surface of the plate by means of an elastic substance such as sponge, fabric or the like.

In order to omit the treatment for rubbing the surface of the plate by means of the elastic substance after the aftertreatment in the fourth trough 22D. or to make the treatment, easier, a removing means may be provided in the fourth trough 22D, i.e., which provides the same effect as the optional removing device provided in the second trough 22B for the purpose of removing the silver halide emulsion layer. More precisely, the hydrophilic surface part or the hydrophilic layer which has been deteriorated in the third trough 22C and any remaining silver halide emulsion layer are removed by means of sponge rollers 27 and a pressing plate 28. Any substance may be used for this removing means which has a removing effect and which does not damage the surface of the plate.

The plate on which the treatment in the treating trough 22D has been completed is optionally put on a receiving plate 31 to be an original plate for printing via a drying device provided at the end part of the apparatus 10.

FIG. 2 shows an apparatus for a photo-platemaking process which comprises the apparatus shown in the FIG. 1 with a camera device combined therewith. More precisely, this apparatus is composed of a manuscript supporting bed 8, a photomagnification controlling device for changing the relative position ofa mirror 4 and a lens 5, a device for conveying a plate substance to the photoengraving device and for cutting off the conveyed part. the plate substance having been photographed in the interior of a camera device. e.g.. by photographing the image of the manuscript on the plate substance in the form of a roll which has been housed in the magazine box 1, by means of the mirror 4 and the lens 5, and photo-engraving apparatus as shown in the FIG. 1.

The manuscript supporting bed 8 is movable parallel to the surface of the floor to change the relative position with the lens series device in order to obtain any desired photograph such as magnified, equivalent or reduced by means of the photomagnification controlling device.

For photography, the manuscript is fixed on the manuscript supporting bed 8 by means of a glass plate so as to keep the manuscript even.

A light projector 7 is movable so as to evenly light the surface of the manuscript. When the intensity of illum ination on the manuscript bed is increased by using a plurality of light sources, the luminance of the respective light source may often vary individually with the lapse of time. ln order to avoid such individual variation of the illumination, the relative position and angle of the light source and the manuscript supporting bed are adjustable.

It is necessary that a positive image of the manuscript be photographed on the printing plate substance by means of the camera device 9. For this purpose, the mirror 4, a prism 01' the like, is incorporated in the optical system. The lens 5 and a shutter iris are similar to the lens system of a photoengraving camera. Elements 2 and 3 are explained in detail in the discussion regarding FIG. 3.

FIG. 3 illustrates the interior of magazine box 1. The leading end part ofa plate substance 12 which has been rolled up in the form of a roll in a spool 11 is conveyed via roller twins l3 and guide plates and the plate substance is kept in a flat state on a plate supporting plate 15, that is, in the position where the plate substance is photographed, by means of roller twins l3 and 13'. The photosensitive material 12 may be positioned by applying suction to the material 12 under vacuum from the back surface of the light-sensitive surface thereof or by pressing the whole surface of the material 12 on the camera back 15 by means of a plate which is transparent to light.

The plate substance 12 is conveyed downward by means of the rollers 13 and after a plate having a deter mined size has been conveyed to the desired position by the action of a cam 17 which is operated by a timer (not shown) the plate 12 is cut in the form of a sheet by means of a cutter 16 which is set to cooperate with the cam 17. The thus cut sheet is conveyed to the photo-engraving apparatus via a slit 18 in a flexible skirt 3. 19 is a guide to forward the cut plate substance to the processor.

A light-excluding curtain 14 is slidable so as to cover the front surface of the plate 15 by operating a handle 2 at the outside of the magazine box 1, whereby the plate substance 12 may economically be utilized according to the size of the manuscript.

As the plate substance, a sheet-type substance may, of course, be used.

The process of photographing and conveying the plate substance to the photoengraving apparatus will now be explained with reference to the combination apparatus of the camera device 9 and the photoplatemaking apparatus 10.

A manuscript evenly set on the manuscript supporting bed 8 is kept at the necessary photomagnification by appropriately controlling the positions of the supporting bed 8 and the lens 5 according to the desired photomagnification. Next, the manuscript is photographed on the plate substance which has been prepared on the plate supporting plate 15 by means of the lens 5. After the completion of the photographing, the plate substance is conveyed in the necessary length by the roller twins l3 and 13 and is cut by the cutter 16. The cut plate substance sheet is conveyed to the photoengraving apparatus via slit 18 in the skirt 3. On the other hand, the remaining plate substance roller 12 is kept on the plate supporting plate 15 and is prepared for the next photographing.

The treatments to be performed thereafter in the respective treating troughs of the photo-platemaking apparatus have already been explained hereinbefore in detail.

According to the photo-platemaking apparatus of the present invention continuous processing from the photographing of a manuscript to the photo-platemaking of printing plate may automatically be performed even in a light room by operating a control box (not shown) for the apparatus.

As will be apparent from the above explanation. the process and the apparatus of the present invention have the following merits.

1. Printing plates may be produced having good reproductivity and a high printing resistance, which plates may therefore reproduce print reproductions having an excellent image quality. This effect becomes particularly noticeable after the after-treatment has been performed.

2. Printing plates may be produced which can be visually checked by the coloration thereof without ink- 3. The silver halide emulsion layer after being developed may be completely removed by means of a pair of twin rollers in the water washing trough for the removal of the silver halide emulsion layer without any formation of foam in the washing water. This effect is favorable for the treatments after washing.

4. Printing plates may be produced speedily and simply by one operator.

5. Printing plates may be produced automatically and speedily in a light room by one operator.

The above mentioned merits are particularly noticeable when the process of the present invention is combined with the apparatus of the present invention, and more preferably, it is advantageous to use a hydrophilic surface part for obtaining practical effects. Sufficient effects may, of course, be obtained by means of the other embodiments.

The present invention will now be explained in more detail by the following examples which. however, do not limit the scope of the present invention.

EXAMPLE 1 Solution A Glycerin 50 ml Methyl alcohol 300 ml Sodium sulfate (9 H 0) 12 g Sodium carbonate (l H O) 0.5 g Water lU ml Solution B Cadmium acetate (2 H. -O) 13.3 g Water 10 ml Solution B was added to Solution A over minutes (while being stirred) to form Solution C wherein cadmium sulfate was dispersed. 100 g of the Solution C were mixed with Solution D of the following composition to prepare Solution E.

Solution D Water 800 ml Sodium hydroxide 200 ml Ethyl alcohol I200 ml A cellulose triacetate sheet having a thickness of l35[.L was dipped in Solution E for 40 seconds at 40C and was washed with warm water and dried, .whereby an image receiving sheet for diffusion transfer printing was formed.

A silver bromoiodide emulsion (5 mol of silver iodide) containing 1.2 mols of silver per 1 kg of emulsion which was ortho-sensitized by means of a sensitizing dye was applied in a thickness of Sp. to the sheet.

The silver halide emulsion layer was image-wise exposed and then developed using a developer of the following constitution for 30 seconds at 20C.

Developer composition Water 750 ml p-Methyl-aminophenol sulfate 5 g Sodium sulfite anhydride 65 g Sodium thiosulfate anhydridc g Hydroquinone l5 g Sodium hydroxide g Water to make 1000 ml After development, the sheet was dipped in warm water at 50C while keeping the silver halide emulsion layer in contact with the hydrophilic surface part, whereby the silver halide emulsion layer was removed from the hydrophilic surface part. At this time a positive silver image deposited by the development is present in the hydrophilic surface layer.

The hydrophilic surface part was then dipped in an etch-bleaching solution of the following constitution for seconds at 15C.

Etch-bleaching solution composition Cupric chloride (2 H 0 10 g Acetic acid 10 g Peroxoammonium disulfate l20 g Water to make 1500 ml In this stage the hydrophilic surface part containing the silver image was deteriorated. In order to completely remove the deteriorated part, however, the surface had to be strongly rubbed by means of cotton, wool or another soft fabric. The cellulose triacetate sheet having a hydrophilic surface part and an oleophilic part which has been obtained at this stage may be used as a prin tingplate as such.

The cellulose tri-acetate sheet which was subjected to the etch-bleaching treatment was further dipped in an aftertreating solution of the following constitution at 40C for 20 seconds.

32 g 950 ml The deteriorated residue in the silver image part was removed very easily from the after-treated hydrophilic surface part. The thus obtained printing plate was colored in the non-image parts (that is, the part not containing any silver image), and thus it was confirmed that the etching was accurately completed.

This printing plate was set on an offset printing machine for printing and 5,000 print reproductions were obtained. During printing, the hydrophilic property of the non-image part of the printing plate was not damaged and scratches did not occur on the surface of the printing plate, and so the image lines of the produced prints were very sharp. This means the printing resistance of the printing plate obtained according to the above mentioned process is superior to that of a printing plate which was obtained merely by the etchbleaching treatment or without the after-treatment.

EXAMPLE 2 A cellulose diaeetate sheet (thickness 155a) was dipped in the following Solution D for 45 seconds at 40C, whereby the surface part of the sheet was hydrolyzed to become hydrophilic and, at the same time, nickel sulfate was introduced in the said surface part. An image receiving sheet for diffusion transfer was thus obtained.

Solution A Glycerin 100 g Ammonium sulfate (aqueous solution wherein the sulfur content is H.371) 40 ml Solution B Glycerin I Nickel nitrate 6 H O) 0.5

Solution A and Solution B were mixed together at 30C over 5 minutes (while being stirred) to form Solu' tion C. 250 g of Solution C were mixed with a solution consisting of 3,000 g of methyl alcohol, 2,000 g of water and 500 g of sodium hydroxide to form Solution D.

To the above mentioned image receiving sheet there was applied, at a thickness of 3,u., an emulsion layer of silver bromochloride (silver chloride 75 mol which contained 1 mol of silver per 1 kg of emulsion and which was subjected to gold sensitization and which had been ortho-sensitized by means of a sensitizing dye. This silver halide emulsion layer was image-wise exposed and developed for 25 seconds at 25C using the following developer.

Developer composition Sodium sulfite anhydride g Hydroquinone 20 g l-Phenyl pyrazolidone 1,0 g Sodium thio-sulfate 10 g Potassium bromide 25 g Potassium hydroxide l8 g Water to make 1000 ml After development, the sheet was dipped in warm water at 55C, the silver halide emulsion layer and the hydrophilic surface part being kept in contact. whereby the silver halide emulsion layer was removed from the hydrophilic surface part.

Next. the hydrophilic surface part was dipped in an etch-bleaching solution consisting of the following components for 25'seconds at 25C.

Etch-bleaching solution composition (upric sulfate (5 H 20 g Citric acid g Potassium bromide g Peroxoammonium disulfatc 65 g Water to make lUUU ml After-treating solution composition (.l. Direct Orange 39 g Sodium carbonate l g Water l()()() ml The deteriorated residues in the silver image part were easily removed from the hydrophilic surface part thus after-treated merely by lightly rubbing the surface with a soft sponge.

The non-image part of the thus obtained printing plate was Colored and checking of the plate was easy..

The plate was subjected to offset printing and 6000 sharp reproductions were obtained.

EXAMPLE 3 Silver was coated by vacuum evaporation coating a cellulose triacetate film. and then the film was dissolved in methylene chloride. A polyethylene terephthalate film (thickness 100a) coated with a gelatin subbing layer was coated with the solution resulting from the dissolution at a thickness of about 4a.

This sheet was hydrolyzed with a solution consisting of the following components to form a hydrophilic surface part about 1.2,u. thick containing silver depositing nuclei.

Hydrolyzing solution composition Lithium hydroxide g Ethylene glycol ltll) g Methyl alcohol 550 g Water Onto the hydrophilic surface layer a silver chloride emulsion layer (ratio of silver to gelatin 1:2) was coated at a thickness of about 4p., and then the emulsion layer was image-wise exposed.

This plate substance was then dipped in a developer of the following constitution for 30 seconds at 20C.

Developer composition Sodium sulfite anhydride 75 g Hydroquinone I8 g Sodium thio-sulfale anhydride ll) g Potassium bromide 2 g Potassium hydroxide 19 g Water to make I000 ml After development. the plate was washed with water at 40C for 30 seconds while the layers were kept in contact. By the washing the silver halide emulsion layer was removed and a positive silver image was deposited on the hydrophilic surface part.

This plate was treated with an etch-bleaching solution of the following constitution for 30 seconds at 25C.

Etch-bleaching solution composition Cupric bromide o g Phosphoric acid 0 ml Pcroxopotassium disulfatc l-H) g Water to make 1000 ml At this stage. the hydrophilic surface part containing the silver image was deteriorated. In order to completely remove the deteriorated part. however. the surface had to be strongly rubbed by means of a fabric or sponge.

The hydrophilic layer subjected to the etch-bleaching treatment was then dipped in an after-treating solution of the following composition at C for 14 seconds. whereby a printing plate having high printing resistance and able to reproduce a printed image of good sharpness was obtained.

After-treating solution composition Cl. Direct Blue 71 Water 30 g lUUU ml This printing plate was used for offset printing and 8000 print reproductions of high quality were obtained.

EXAMPLE 4 A cellulose acetate butyrate sheet having a thickness of 38p. and a polyethylene terephthalate sheet 100p. thick were laminated and hydrolyzed for 6 minutes at 20C using the following solution:

Water 500 g Methyl alcohol 500 g Sodium hydroxide v The sheet whose surface part was hydrolyzed was neutralized by means ofa 57: acetic acid aqueous solution and was then washed with water and dried. This sheet was dipped in a 0.0371 chloroaurate-methyl alc0- hol solution at 35C for 30 seconds and then dried. It is preferred to use ultra-violet drying. though even without such if the sheet is left as such at normal temperature for 1 day sufficient amounts of diffusion transfer nuclei are deposited in the hydrolyzed surface part of the cellulose triacetate sheet.

A silver bromochloride emulsion layer (silver chloride 70 mol 7:) containing 1 mol of silver per l kg of emulsion was coated on the sheet at a thickness of 3 ,u, and then the layer was exposed image-wise and developed for 40 seconds at 25C using a developer of the following composition:

Water 750 ml p-Mcthyl-aminophenol sulfate 5 g Sodium sulfite anhydridc 65 g Hydroquinonc g Potassium thiocyanatc 25 g Sodium hydroxide g Water to make 1000 ml After the silver halide emulsion layer was removed in warm water at 50C, a positive silver image was obtained. I

The plate was next immersed in an etching-bleaching solution of the following composition at C for seconds.

Cupric bromide (2 H 0) 12 g Glacial acetic acid 50 ml 357/ Hydrogen peroxide solution I00 ml Water 900 ml After-treating solution con'iposition Z-Hydroxy-naphthalene-3carboxyanilinc-4'- sodium sulfonatc Water to make I000 ml EXAMPLE 5 A polystyrene sheet (thickness 120 ,u.) was dipped in concentrated sulfuric acid for 10 seconds at 50C to sulfonate the surface part thereof, washed with water and then dipped in a 1N sodium hydroxide solution to neutralize the acid. The sheet was again washed with water and dried.

Next, this sheet was dipped in a dispersion of colloidal nickel sulfide which was formed in 80 g of ethylene glycol monobutyl ether, 15 g of methyl alcohol and 5 g of water (colloidal nickel sulfide concentration 3 X 10" mols/l for 60 seconds at 30C to introduce nickel sulfate into the surface part, whereby a sheet having a transparent hydrophilic surface part was obtained.

A silver chloride emulsion layer wherein the ratio of silver to gelatin was 1:2 was coated on this surface, and then the layer was exposed and washed with water as in Example 3. A black positive silver image was thus obtained. This was treated with the etching-bleaching solution of Example 1 for 25 seconds at 30C and then further treated with the following solution for 30 seconds at 25C to obtain a printing plate.

(.l. Direct Red. 31 Water to make 1000 ml vided on an oleophilic support and containing therein silver depositing nuclei for a diffusion transfer process and a silver halide emulsion layer superimposed thereon, and then developing the exposed plate substance to form a positive silver image on the hydrophilic surface part or on the hy drophilic layer,

. washing the developed plate substance with water to remove the silver halide emulsion layer,

3. subjecting the hydrophilic surface part or the hydrophilic layer to an etch-bleaching treatment to thereby deteriorate the hydrophilic surface part which corresponds to the silver image,

. subjecting the product of step (3) to an after treatment which is conducted with either a 0.1 to 20% by weight solution of KSCN, based on one liter of after treatment, at a temperature from about 5 to about C, or with a solution of a dyestuff which is a direct dye, basic dye, naphthol dye, or acid with an anionic substituent of a sulfonic group, sulfinic group, -CO group, CS group or carboxyl group, and whereby the dyestuff is physically adsorbed to the hydrophilic surface part or hydrophilic layer, whereby the residues of any etchedbleached portions are made brittle and fragile, and

-5. removing the residues.

2. The process of claim 1 where the hydrophilic materials have a contact angle with water less than 45C and the oleophilic support has a contact angle with water greater than 45. at normal temperature.

3. The process of claim 2 where the oleophilic support is a cellulose ester.

4. The process of claim 1 where the total thickness of the oleophilic support and the hydrophilic surface part or layer is from about 80 to about 300a.

5. The process of claim 4 where the hydrophilic surface part or layer is about 0.1 to about 30 t thick.

6. The process of claim 1 where the silver depositing nuclei are present only in hydrophilic materials.

7. The process of claim 1 where development is with a diffusion transfer developer comprising a developing agent and a solvent for dissolving silver halide.

2 to 90C. the treatment period being 5 seconds to 5 minutes.

12. The process of claim 11, wherein the concentration is 0.5 to about 5%, the pH is 7 to l l, and the temperature is l0 to 50C.

13. The process of claim I, wherein said solution of said dyestuff is an aqueous solution containing also from 2 to 6071 based on the solution weight of an organic solvent which is miscible with water.

14. The process of claim 13, wherein said organic solvent is present in an amount from 2 to 20%. 

1. A PHOTO-PLATEMAKING PROCESS FOR MAKING PRINTING PLATES WHICH COMPRISES THE STEPS OF:
 1. IMAGE-WISE EXPOSING A PLATE SUBSTANCE FOR MAKING A PHOTOPLATE, WHICH PLATE SUBSTANCE CONSISTS OF A HYDROPHILIC SURFACE PART OR A HYDROPHILIC LAYER PROVVIDED ON AN OLEOPHILIC SUPPORT AND CONTAINING THEREIN SILVER DEPOSITING NUCLEI FOR A DDIFFUSION TRANSFER PROCESS AND A SILVER HALIDE EMULSION LAYER SUPERIMPOSED THEREON, AND THEN DEVELOPING THE EXPOSED PLATE SUBSTANCE TO FORM A POSITIVE SILVER IMAGE ON THE HYDROPHILIC SURFACE PART OR ON THE HYDROPHILIC LAYER,
 2. WASHING THE DEVELOPED PLATE SUBSTANCE WITH WATER TO REMOVE THE SILVER HALIDE EMULSION LAYER,
 2. washing the developed plate substance with water to remove the silver halide emulsion layer,
 2. The process of claim 1 where the hydrophilic materials have a contact angle with water less than 45*C and the oleophilic support has a contact angle with water greater than 45*, at normal temperature.
 3. The process of claim 2 where the oleophilic support is a cellulose ester.
 3. subjecting the hydrophilic surface part or the hydrophilic layer to an etch-bleaching treatment to thereby deteriorate the hydrophilic surface part which corresponds to the silver image,
 3. SUBJECTING THE HYDROPHILIC SURFACE PART OR THE HYDROPHILIC LAYER TO AN ETCH-BLEACHING TREATMENT TO THEREBY DETERIORATE THE HYDROPHILIC SURFACE PART WHICH CORRESPONDS TO THE SILVER IMAGE,
 4. SUBJECTING THE PRODUCT OF STEP (3) TO AN AFTER TREATMENT WHICH IS CONDUCTED WITH EITHER A 0.1 TO 20% BY WEIGHT SOLUTION OF KSCN, BASED ON ONE LITER OF AFTER TREATMENT, AT A TEMPERATURE FROM ABOUT 5* TO ABOUT 80*C, OR WITH A SOLUTION OF A DYESTUFF WHICH IS A DIRECT DYE, BASIC DYE, NAPHTHOL DYE, OR ACID WITH AN ANIONIC SUBSTITUENT OF A SULFONIC GROUP, SULFINIC GROUP, -CO2//2- GROUP, -CS2**2GROUP OR CARBOXYL GROUP, AND WHEREBY THE DYESTUFF IS PHYSICALLY ADSORBED TO THE HYDROPHILIC SURFACE PART OR HYDROPHILIC LAYER, WHREBY THE RESIDUES OF AY ETCHEDBLEACHED PORTIONS ARE MADE BRITTLE AND FRAGILLE AND,
 4. subjecting the product of step (3) to an after treatment which is conducted with either a 0.1 to 20% by weight solution of KSCN, based on one liter of after treatment, at a temperature from about 5* to about 80*C, or with a solution of a dyestuff which is a direct dye, basic dye, naphthol dye, or acid with an anionic substituent of a sulfonic group, sulfinic group, -CO22- group, -CS22- group or carboxyl group, and whereby the dyestuff is physically adsorbed to the hydrophilic surface part or hydrophilic layer, whereby the residues of any etched-bleached portions are made brittle and fragile, and
 4. The process of claim 1 where the total thickness of the oleophilic support and the hydrophilic surface part or layer is from about 80 to about 300 Mu .
 5. The process of claim 4 where the hydrophilic surface part or layer is about 0.1 to about 30 Mu thick.
 5. removing the residues.
 5. REMOVING THE RESIDUES.
 6. The process of claim 1 where the silver depositing nuclei are present only in hydrophilic materials.
 7. The process of claim 1 where development is with a diffusion transfer developer comprising a developing agent and a solvent for dissolving silver halide.
 8. The process of claim 7 where etch-bleaching is with an aqueous etch-bleaching bath comprising an oxidizing agent.
 9. The process of claim 8, wherein said oxidizing agent is peroxosulfate, peroxodisulfate or hydrogen peroxide.
 10. The process of claim 1, wherein said dyestuff is an acid dye and said after treatment is carried out at a temperature of 50* to 90*C.
 11. The process of claim 1, wherein said dyestuff is present in an amount greater than 0.01% by weight of the solution, the pH is alkaline, and the temperature is 2* to 90*C, the treatment period being 5 seconds to 5 minutes.
 12. The process of claim 11, wherein the concentration is 0.5 to about 5%, the pH is 7 to 11, and the temperature is 10* to 50*C.
 13. The process of claim 1, wherein said solution of said dyestuff is an aqueous solution containing also from 2 to 60% based on the solution weight of an organic solvent which is miscible with water.
 14. The process of claim 13, wherein said organic solvent is present in an amount from 2 to 20%. 